GUANTANAMO BAY NAVAL BASE, Cuba - An American military tribunal sentenced an Australian to nine months in prison Friday after he pleaded guilty to supporting terrorism - in the first conviction at a U.S. war-crimes trial since World War II.

A panel of military officers had recommended a term of seven years, but a section of a plea agreement that had been kept secret from the panel capped the sentence at nine months for David Hicks, who has been held at the U.S. military prison at Guantanamo Bay for more than five years.

Under the agreement, the confessed Taliban-allied gunman will be allowed to serve his sentence in an Australian prison, but must remain silent about any alleged abuse while in custody.

Hicks, the first detainee convicted at Guantanamo Bay, appeared relieved as the judge, Marine Corps Col. Ralph Kohlmann disclosed the agreement.

Asked if the outcome was what he was told to expect, Hicks said, "Yes, it was."

Hicks told Kohlmann earlier Friday that he agreed to plead guilty because prosecutors had enough evidence to convict him. Speaking in a deep voice, Hicks said he faced damning evidence taken from "notes by interrogators" that he had been shown.

Hicks, a former outback cowboy who acknowledged aiding al-Qaida during the U.S.-led invasion of Afghanistan, showed little emotion at both hearings Friday as details emerged of a plea deal struck Monday that also requires silence about any alleged abuse while in custody.

Hicks expressed regret for his actions in a statement read by his lawyer, Marine Corps Maj. Michael Mori, who described his client as an immature adventurer who had tried to enlist in the Australian army but was rejected for lack of education.

"He apologizes to his family, he apologizes to Australia and he apologizes to the United States," said Mori, who called for a sentence of 20 months.

The lead prosecutor, Marine Lt. Col. Kevin Chenail, said Hicks deserves the maximum punishment for betraying the freedoms he was raised with in Australia. He argued al-Qaida gave him advanced training because his Western features made him a valuable operative.

"Today in this courtroom we are on the front line of the war on terrorism, face to face with the enemy," said Chenail, who referred to Hicks by his alias "Muhammad Dawood."

"Muhammad Dawood will always be a threat unless he changes his beliefs and his ideology," he said.

Under his plea deal, Hicks stipulated that he has "never been illegally treated by a person or persons while in the custody of the U.S. government," Kohlmann said. In the statement read by Mori, Hicks thanked U.S. service members for their professionalism during his imprisonment. Furthermore, the judge said, the agreement bars Hicks from suing the U.S. government for alleged abuse, forfeits any right to appeal his conviction and imposes a gag order that prevents him speaking with news media for a year from his sentencing date. Hicks previously reported being beaten and deprived of sleep during his more than five years at the prison erected for terrorism suspects held at this U.S. Navy base. Hicks' father, Terry Hicks, welcomed the leniency of a nine-month prison sentence but vowed Saturday to continue complaining about his son's treatment, even though his the younger Hicks is barred from doing so by the plea deal. "I believe one of provisos was that he had to sign a form to say he wasn't badly treated," Terry Hicks told Australian Broadcasting Corp. radio in Australia. "We know for a fact that he was, and I'm going to push that issue." Shayana Kadidal, an attorney with the Center for Constitutional Rights, which represents hundred of Guantanamo detainees, said the provisions appeared aimed at preventing abuse allegations from emerging and politically damaging the Bush administration. U.S. officials have been accused by human rights groups of permitting torture of detainees in the wake of the Sept. 11 terror attacks on the United States. Hicks, who was captured in Afghanistan in December 2001, had faced a maximum sentence of life in prison. He entered a guilty plea Monday night, but he was not formally convicted until Kohlmann accepted his plea at Friday's session. Australia's conservative prime minister, John Howard, who supports the U.S. campaigns in Afghanistan and Iraq, has faced growing pressure for Hicks, one of the first detainees to arrive at the camp in January 2002, to be returned home ahead of elections later this year. At the hearing, Hicks wore a gray suit with a maroon tie, his hair newly shorn. He previously wore a tan prison uniform and his hair hung below his shoulders. His lawyers said he had kept his hair long to help block out the round-the-clock lighting in his cell. Hicks had also been charged with supporting terrorist acts. That count was dismissed as part of the agreement. Under the deal, he will also be required to cooperate with U.S. and Australian authorities to share his knowledge of al-Qaida and a militant Pakistani group, Lashkar-e-Tayyaba, which helped him travel to Afghanistan to attend terrorist training camps. "Any failure to cooperate with U.S. or Australian law enforcement may delay your release from confinement," Kohlmann warned. Another condition calls for Hicks to hand over to the Australian government any proceeds from selling the rights to his life story. In the days before his arraignment Monday, Hicks' lawyers said their client was severely depressed and eager to leave Guantanamo. He spent the last few months alone in a small, solid-walled cell. His father, Terry Hicks, suggested he pleaded guilty only to escape the isolated prison. Hicks is the only detainee who has been formally charged under a new military tribunal system. Prosecutors say they plan to charge as many as 80 of the 385 men now held at Guantanamo on suspicion of links to al-Qaida or the Taliban. The U.S. Supreme Court, which in June struck down the previous military tribunal system at Guantanamo as unconstitutional, is considering a challenge to the revised tribunals. Some members of Congress have vowed to repeal the law that eliminates detainees' access to U.S. courts. AP-CS-03-30-07 2247EDT